As one of the most widely existing post-translational modification models, ubiquitination regulates diverse cellular activities. In eukaryotes, K-branched ubiquitin chains play key roles in cell cycle and protein qual...As one of the most widely existing post-translational modification models, ubiquitination regulates diverse cellular activities. In eukaryotes, K-branched ubiquitin chains play key roles in cell cycle and protein quality control. However, the structural and biochemical properties of K-branched ubiquitin chains have not been well examined. Here we employed the synthetic linkage-and length-defined K-branched ubiquitin chains to examine their binding and hydrolysis properties in vitro. Quantitatively affinity determination of ubiquitin chains to the proteasome ubiquitin receptor S5 a indicated that the S5 a exhibited preference binding to K-branched chains over K-linked chains, but not K-conjugated chains. In addition, deubiquitination experiments were carried out and the results showed that K-branched chains were preferably hydrolyzed by proteasome-associated deubiquitinase Rpnll than homotypic Kor K-linked chains.展开更多
基金supported by the National Natural Science Foundation of China(Nos. U1732161, 91753120)
文摘As one of the most widely existing post-translational modification models, ubiquitination regulates diverse cellular activities. In eukaryotes, K-branched ubiquitin chains play key roles in cell cycle and protein quality control. However, the structural and biochemical properties of K-branched ubiquitin chains have not been well examined. Here we employed the synthetic linkage-and length-defined K-branched ubiquitin chains to examine their binding and hydrolysis properties in vitro. Quantitatively affinity determination of ubiquitin chains to the proteasome ubiquitin receptor S5 a indicated that the S5 a exhibited preference binding to K-branched chains over K-linked chains, but not K-conjugated chains. In addition, deubiquitination experiments were carried out and the results showed that K-branched chains were preferably hydrolyzed by proteasome-associated deubiquitinase Rpnll than homotypic Kor K-linked chains.
